Remember, he used an American Ale yeast, not a lager yeast or even Kolsch. A D-rest could help, but it’s not really necessary if he keeps his ferment in the mid to high 60s anyhow for 3-4 weeks.
There is no reason to bring this beer into the 50’s. In fact it could just screw the yeast up more. Let the beer ferment out in the mid 60s. When ferment is done in 3-4 weeks, you can raise the temp into the 70’s if you would like a D-rest (optional), cold-crash down to low 30s to help clear the beer (optional), or just bottle as you normally would.